Hearing aid



FIG. 1 is a side view of a hearing aid of our design;

FIG. 2 is another side view of the hearing aid of our design;

FIG. 3 is a perspective view of the hearing aid of our design;

FIG. 4 is another perspective view of the hearing aid of our design;

FIG. 5 is another perspective view of the hearing aid of our design;

FIG. 6 is another perspective view of the hearing aid of our design; and,

FIG. 7 is another perspective view of the hearing aid of our design. 

CLAIM The ornamental design for a hearing aid, as shown and described. 